I used to teach Mass Communication. Back in the early days of television, companies openly sponsored shows and their products were often part of the storyline. (Refer to old game shows such as "I've Got a Secret" and the obvious display of Winston Cigarettes and the actors smoking them during the show.) Later in the 1960's tv tried to be more socially conscious, possibly as a result of our involvement in the Vietnam War. Liquor and cigarette ads were banned from the airwaves.

Norman Lear set out to create a pattern of breaking all the rules (refer to "All in the Family") and he was very successful. I think he placed the products overtly for the relaity factor that was so very much his signature style. Later, in movies, especially in the 80's and 90's, advertising insert or product placement became an industry unto itself. Example: Did the plane in Cast Away really have to be a Fed Ex Carrier? The promo and publicity generated from this type exposure far outweighs the money paid to place the product.